Physiology of drought tolerance of clusterbean and moth bean

摘要

Clusterbean and moth bean the most important arid legumes, possess different mechanisms of drought resistance to survive and produce under drought-prone environments. The development of short duration and early maturing varieties that enable the cropto escape severe soil moisture deficits is of paramount importance in these legumes. Both these legumes display several mechanisms of dehydration avoidance to maintain turgor potential for normal metabolic functioning under water deficits. These comprisemaximization of water uptake through deep and extensive root systems and reduction of water loss by appropriate shoot attributes and osmotic adjustment for continued photosynthesis and growth at low water potentials. Significant genotypic differences exist for different physiological attributes and drought resistance traits which need to be better understood for selection and development of drought tolerant genotypes with higher yield potential under water limited conditions. Both the legumes are mostsensitive to water stress at the flowering stage and genotypic differences at this critical stage are most important. Maintenance of higher leaf turgidity, net photosynthetic rate and stomatal conductance at similar stress levels, alongwith least alterations in leaf metabolites in moth bean was also reflected in its higher yield stability under water stress as compared to clusterbean and other legumes. In addition to drought tolerance characteristics, various improved cultural practices, optimum plant nutrition and adoption of drought ameliorative measures must be considered to reduce drought injury and to obtain sustainable crop yields under arid environments.